Video recording medium for stop-motion playback

ABSTRACT

A video record medium, such as a record disc, for recording a composite video and audio signal suitable for stop-motion playback, with accompanying audio. Discrete segments of an analog audio signal are digitized and compressed in time and recorded on alternate tracks on the disc, and corresponding frames of a video signal are recorded on the tracks located therebetween. During playback of the disc, a selected audio track is scanned initially and the digital audio data recovered therefrom is entered into a memory device, after which the track for recording the corresponding video frame is scanned in a repeated fashion, to produce a stop-motion display of the frame, while the stored audio data is extracted from the memory device and converted back to an analog format, for simultaneous playback at its original speed.

This is a continuation of application Ser. No. 07/526,004, filed on May21, 1990, which was abandoned; which is Rule 60 continuation of Ser. No.07/782,166 filed Oct. 2, 1985 which is allowed as U.S. Pat. No.5,018,020; which is a continuation of Ser. No. 06/458,596 filed Jan. 17,1983 abandoned, which is a continuation of 06/331,958 filed Dec. 18,1981 abandoned; which is a Rule 60 division of Ser. No. 06/066,620 filedJun. 15, 1979 abandoned.

BACKGROUND OF THE INVENTION

This invention relates generally to record media for recording videosignals and, more particularly, to record media for use with playbackapparatus to produce stop-motion video displays.

Record media of this particular type have typically been in the form ofrecord discs and have recorded composite signals that contain both avideo signal and an audio signal, simultaneously. The composite signalis normally recorded in a succession of substantially circular andconcentrically arranged recording tracks on the disc, with eachsuccessive frame of the signal being recorded on a separate track.Stop-motion of a selected video frame is normally accomplished byrepeatedly scanning a single track. Since the corresponding audio signalwould be meaningless it if, too, were repeated successively, it isnormally squelched during this stop-motion playback.

One technique for providing playback of an audio signal while displayinga stop-motion video frame is to record the same video signal on a numberof successive recording tracks, but with a unique portion of the audiosignal recorded on each track. In this manner, the composite signal canbe played back from the record disc in a conventional manner, and thevideo display will appear to be in stop-motion, but will be accompaniedby a normal audio signal. While this technique may prove satisfactory insome situations, it can sometimes be unduly wasteful of recording spaceon the record disc.

It will thus be appreciated that there is a need for a video recordingmedium, along with apparatus for formatting a composite signal forrecording on the medium and apparatus for suitably processing the signalrecovered from the medium, wherein the video signal can be played backin a stop-motion fashion, with an accompanying audio signal, while usinga minimum number of recording tracks on the medium. The presentinvention fulfills this need.

SUMMARY OF THE INVENTION

The present invention is embodied in a record medium for recording aspecially-formatted composite signal that includes both a video signal,representative of a video frame, and a corresponding audio signal,wherein the medium is suitable for use with special playback apparatusfor displaying the video frame, in a repeated fashion, while accompaniedby a playback of a corresponding analog audio signal. In accordance withthe invention, the audio signal is recorded in a special time-compressedformat on a first portion of the medium, and the video signal isrecorded on a second portion of the medium, whereby apparatus forplaying the record medium can operate to re-create the analog audiosignal corresponding to the time-compressed audio signal, while thevideo frame is being displayed, repeatedly, a prescribed number oftimes.

More particularly, a record medium in accordance with the presentinvention is in the form of a record disc having a succession ofsubstantially circular and concentrically arranged recording tracks. Thespecial time-compressed audio signal is recorded on alternate tracks onthe disc, and the corresponding frames of the video signal are recordedon the tracks therebetween. The audio signal is preferably in a digitalformat, and is arranged in a succession of bit packets that areinterleaved with conventional periodic video synchronization signals,whereby the recorded audio signal has the appearance of a conventionalvideo signal with a luminance value that alternates between white andblack levels. Additionally, the bit rate of the successive bit packetsin the recorded digital audio signal is synchronized with the frequencyof periodic chrominance burst signals included in the videosynchronization signals, thereby further simplifying detection duringplayback.

The recorded disc is suitable for playback in a stop-motion fashion,wherein each of the recorded video frames is displayed, in a repeatedfashion, a prescribed number of times, while, simultaneously, thecorresponding digital audio signal is converted back to an originalanalog format, for playback at its original speed. Thus, a stop-motionvideo sequence can be achieved, with accompanying audio, while utilizinga minimum number of recording tracks.

Apparatus in accordance with the present invention, for recording thecomposite signal on the video record disc, includes digitizing means forconverting a conventional analog audio signal into a correspondingdigital audio signal having a relatively low bit rate, for clocking intoa digital memory device. The apparatus further includes means forclocking the digital data out of the memory to produce a succession ofbit packets having a relatively high bit rate, along with means forcombining the bit packets with periodic synchronization signals toproduce the special digital audio signal for recording on the disc. As aresult of the increase in bit rate, the original audio information issubstantially compressed in time, permitted approximately 13 seconds ofaudio information to be recorded on a single track.

The digitizing means preferably comprises a delta modulator, wherebyspecial digital synchronization signals for the digital data are notrequired. Also, the digital audio signal is low-pass filtered to limitits bandwidth to approximately that of a conventional video signal. Thisspecially-formatted digital audio signal is then combined, in a serialfashion, with a corresponding video signal, and coupled to aconventional disc mastering machine for recording on the disc.

Apparatus for playing back a video record disc in accordance with thepresent invention includes means for separating the successive packetsof the high bit rate digital audio signal interleaved with the periodicvideo synchronization signals, along with means for loading theseparated packets of data into a digital memory device. The apparatusfurther includes means for clocking the digital data out of the memorydevice at a relatively slow bit rate, corresponding to its originalnon-compressed rate, and means for converting this relatively slowdigital signal into a corresponding analog audio signal for playback atits original speed.

Simultaneous with the playback of each audio signal segment, thecorresponding video signal, recorded on the adjacent track on the disc,is displayed, in a repeated fashion, a prescribed number of times. Eachsuch video frame can include a special code in its vertical interval,indicating the number of times it is to be scanned by the playbackapparatus. After this prescribed number of scans, the apparatus performsthe same procedure for the next audio/video recording track pair.

Other aspects and advantages of the present invention will becomeapparent from the following description of the preferred embodiment,taken in conjunction with the accompanying drawings, which disclose, byway of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of record formatting apparatus inaccordance with the present invention, for producing a composite videosignal that includes a special time-compressed audio signal, forrecording on a video record disc, wherein the recorded disc is suitablefor playback in a stop-motion fashion, with accompanying audio;

FIG. 2 is a simplified block diagram of playback formatting apparatusfor extracting the time-compressed audio signal from the composite videosignal recovered from the video record disc, to re-create thecorresponding analog audio signal for playback while a correspondingvideo frame is being displayed in a stop-motion fashion;

FIG. 3 is a schematic diagram of a video record disc for recording thespecial composite signal produced by the apparatus of FIG. 1, whereinthe time-compressed audio signal and a corresponding video signal arerecorded on alternate tracks on the disc;

FIG. 4 is a block diagram of a videodisc player system of the prior artshowing a scanning means and a display device in combination with otherfunctional blocks;

FIG. 5 is a schematic representation of the optical system block shownin FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, and particularly to FIG. 1, there isshown a record formatting apparatus for formatting a special compositesignal that includes both audio and video information, for recording ona video record disc 11 (FIG. 3). The composite signal is recorded in asuccession of substantially circular and concentrically arrangedrecording tracks 13, and the recorded disc is suitable for playback in astop-motion fashion, wherein a video frame is displayed, repeatedly, aprescribed number of times, while accompanied by playback of acorresponding audio signal.

In accordance with the invention, the composite signal recorded on thedisc 11 is a sequence of information segments alternating between audioinformation segments and corresponding video information segments,wherein each audio segment comprises a digitized and time-compressedaudio signal and each video segment comprises one frame of a videosignal. Additionally, each information segment is recorded on a separatetrack on the disc, so that during playback of the disc, a selected audiotrack can be scanned a single time and the audio segment recordedthereon can be entered into a memory device, after which the audioinformation can be extracted and converted back to an analog format, atits original speed, while the corresponding video track is scanned in arepeated fashion, to produce a stop-motion display of the video framerecorded thereon.

In a preferred embodiment, the apparatus for recovering the compositesignal from a record medium, wherein the composite signal includes atime-compressed audio signal recorded on a first portion thereof and acorresponding video signal recorded on a second portion thereof, andwherein the recovered composite signal is suitable for use in producinga stop-motion display of a video frame represented by the video signal,while accompanied by a playback of an analog audio signal correspondingto the time-compressed audio signal, comprises: apparatus for scanningthe record medium to recover the time-compressed audio signal therefrom;apparatus for storing the audio information represented in the recoveredtime-compressed audio signal; the scanning apparatus being furtheroperable after the time-compressed audio signal has been recovered, torecover the video signal from the record medium; a monitor fordisplaying, in a repeated fashion, the video frame represented by therecovered video signal; and for extracting the audio information fromthe storing apparatus, to produce the analog audio signal correspondingto the time-compressed audio signal, for playback simultaneous with therepeated display of the video frame.

More particularly, the record formatting apparatus of FIG. 1 produces aspecial video/data output signal for coupling to a conventional discmastering machine (not shown), for recording on the disc 11. The signalhas the appearance of a conventional video signal, with its successiveframes alternating between frames of the digitized and time-compressedaudio signal and corresponding frames of the video signal. The audioframes include conventional periodic video synchronizing signals,interleaved with packets of the digital audio data.

Additionally, although the analog audio signal is initially converted toa digital audio signal having a bit rate of only 12 kilobits per second,the time-compressed digital audio signal recorded on the disc 11 has abit rate of about 7.2 megabits per second, whereby its bandwidth iscomparable to that of a conventional video signal. This increases in bitrate compresses the data in time by a substantial amount, wherebyapproximately 13 seconds of audio information can be recorded on asingle recording track on the disc.

As shown in FIG. 1, operation of the record formatting apparatus isinitiated by a sequence controller A 15, by producing a 12 KHz enablesignal. This signal is coupled over line 17 to an audio source 19, suchas an audio tape recorder, enabling it to produce an analog audio signalto be digitized and recorded on the disc 11. This analog audio signal iscoupled over line 21 to an adaptive delta modulator 23, where it isconverted to a corresponding low bit rate digital audio signal. Thedelta modulator is clocked by a 12 KHz clock signal supplied on line 25from a clock generator A 27, which produces the clock signal wheneverenabled by the aforementioned 12 KHz enable signal. One suitableadaptive delta modulator is disclosed in an article written by N. S.Jayant, entitled "Adaptive Delta Modulation with a One-Bit Memory",published in the Bell System Technical Journal, March, 1970.

The digital audio signal produced by the delta modulator 23 has a bitrate of 12 kilobits per second and does not include any specialsynchronization bits. The digital signal is transmitted over line 29 tothe data input terminal of a memory device A 31, where it is loaded bymeans of the 12 KHz clock signal, supplied on line 25 from the clockgenerator A 27. The memory device A can advantageously comprise aboutten 16K×1 dynamic RAM integrated circuits, arranged in a conventionalmanner, whereby approximately 13 seconds of the original analog audiosignal produced by the audio source 19 can be stored.

It will be appreciated that, alternatively, digital audio datarepresentative of an audio signal duration longer than about 13 secondscould be stored for subsequent recording on more than merely onerecording track. This would permit the corresponding video frame to bedisplayed in a stop-motion fashion, with accompanying audio, for aperiod longer than about 13 seconds.

After the memory A 31 has been fully loaded with a segment of thedigitized audio signal, the sequence controller A 15 automaticallyterminates the 12 KHz enable signal, to disable the audio source 19 and,likewise, disable the clock generator A 27 from producing the 12 KHzclock signal. Further clocking of audio data into the memory istherefore terminated. Thereafter, the sequence controller A produces a7.2 MHz enable signal for transmission over line 33 to the clockgenerator A 27, which responds by producing a 7.2 MHz signal forcoupling to the clock out terminal of the memory A, to clock out thestored digital data at a corresponding rate.

A video input signal that includes conventional vertical and horizontalsynchronization pulses, along with conventional chrominance bursts, issupplied to the record formatting apparatus on line 35 from videocircuitry (not shown). For alternate frames when the digitized andtime-compressed audio signal is to be recorded on the record disc 11,the video input signal includes only the periodic synchronizationsignals, whereby the apparatus can operated to interleave packets of thedigitized audio signal therewith.

Accordingly, the 7.2 MHz clock signal is coupled to the clock outterminal of the memory A 31 to clock out the digital audio data onlyduring the periods between the successive synchronization signals. Thisis accomplished utilizing an AND gate 37 to "AND" together the 7.2 MHzsignal and conventional vertical blanking and horizontal blankingsignals, the latter two signals being produced by the sequencecontroller A 15, by continuously monitoring the video input signal.

The vertical blanking signal, which is in the logical "1" state at alltimes except during the vertical interval of the video signal, and thehorizontal blanking signal, which is in the logical "1" state at alltimes except during the successive horizontal blanking intervals, arecoupled over lines 39 and 41, respectively, to two input terminals theAND gate 37. The 7.2 MHz signal is coupled over line 43 from the clockgenerator A 27 to a third input terminal of the AND gate. As a result,clock pulse bursts are produced by the AND gate and coupled over line 45to the clock out terminal of the memory A 31, whereby correspondingpackets of the digital audio data are produced during the appropriatetime intervals.

In accordance with another feature of the invention, the frequency ofthe 7.2 MHz clock signal coupled to the memory A 31 is synchronized withthe frequency of the successive chrominance bursts in the video inputsignal, supplied on line 35. In particular, the frequency of the 7.2 MHzclock signal is exactly 2× that of the chrominance bursts, whichnormally have a frequency of 3.579545 MHz. This facilitates a properdetection of the time-compressed digital audio signal by apparatus forplaying back the recorded disc 11.

To accomplish this frequency synchronization, the sequence controller A15 continuously monitors the video input signal supplied on line 35 andproduces a chrominance burst timing signal that coincides with thetiming of the successive bursts. This timing signal is coupled over line47 to the clock generator A 27, to gate an internal oscillator andenable it to become synchronized, automatically and in a conventionalmanner, with the frequency of the successive bursts.

The successive packets of digital audio data output by the memory A 31,at a bit rate of about 7.2 megabits per second, form a time-compresseddigital audio signal that is coupled over line 49 from the data outputterminal of the memory A to a low-pass filter 51, where the bandwidth ofthe signal is limited to approximately 4.2 MHz. This bandwidth iscomparable to that of a conventional video signal. The filter ispreferably a linear-phase filter, to minimize overshoot and intersymbolinterference.

The filtered digital signal is coupled over line 53 form the low-passfilter 51 to a video normalizer 55, which adjusts the minimum andmaximum values of the filtered signal to levels corresponding to 0 and100 IRE, respectively. As a result, the full dynamic range of subsequentvideo circuitry can be fully utilized. Thereafter, the normalized signalis coupled over line 57 to a summer 59, where it is summed with theaforementioned video input signal, supplied on line 35. The resultingvideo/data output signal has the appearance of a conventional videosignal, but with filtered digital data, rather than conventionalluminance and chrominance information, in alternate frames. This signalis coupled over line 61 to a conventional disc mastering machine (notshown) for recording on the record disc 11.

After all of the digital audio data has been clocked out of the memory A31, i.e., sufficient data to complete one video frame, the 7.2 MHzenable signal is terminated by the sequence controller A 15, and thenext frame of the video/data output signal comprises conventional videoinformation corresponding to the video input signal, supplied on line35. After one frame of video signal has been output, the abovedescribedaudio signal formatting procedure is repeated, beginning with theenabling of the audio source 19 by the 12 KHz enable signal supplied online 17 from the sequence controller A.

The successive alternating frames of audio and video information aredistinguishable from each other by a suitable flag code recorded in aconventional manner in the respective vertical intervals of the frames.This code can advantageously further indicate the prescribed number oftimes each video frame is to be repeatedly displayed during subsequentplayback of the disc 11, while the corresponding time-compressed audiosignal is being converted back to an analog format and played at itsoriginal speed. To facilitate the recording of this code in therespective vertical intervals, the sequence controller A 15 produces adata flag signal, indicating which of the alternate video framesincludes the time-compressed audio signal. This data flag signal iscoupled over line 63 to the disc mastering machine.

With reference now to FIG. 2, there is shown playback formattingapparatus for use in processing a video-data input signal recovered fromthe record disc 11 by a conventional disc player machine (not shown), tore-create the original analog audio signal, for playback while theassociated video frame is being repeatedly displayed the prescribednumber of times. In particular, the apparatus operates to extract thesuccessive packets of digital audio data from the video/data inputsignal and to convert the data back to the original analog audio signal.

As shown in FIG. 2, the video/data input signal is supplied on line 65from the disc player machine to a data normalizer 67, a sequencecontroller B 69, and a clock generator B 71. The data normalizerfunctions to adjust the levels of the input signal such that onalternate frames, when the signal corresponds to the time-compressedaudio signal, the input signal is adjusted to levels suitable forsubsequent digital processing. The sequence controller B monitors thevideo/data input signal and, accordingly, produces a chrominance bursttiming signal, indicating the occurrence of chrominance bursts in theinput signal, and vertical blanking and horizontal blanking signals,indicating the occurrence of vertical and horizontal blanking intervals,respectively, in the input signal. The chrominance burst timing signalis coupled over line 72 to the clock generator B, to gate an internaloscillator and enable it to synchronize with the frequency of thechrominance bursts, which are simultaneously present in the video-datainput signal. This is essentially the same technique as previouslydescribed in connection with the record formatting apparatus of FIG. 1.

In addition to the video/data input signal, a data flag signal iscoupled over line 73 from the disc player machine to the sequencecontroller B 69 of the playback formatting apparatus. This flag signalindicates that the frame of the video/data input signal currently beingsupplied on line 65 contains the time-compressed audio signal. Whenevera data flag signal is received, the sequence controller B outputs a 7.2MHz enable signal for coupling over line 75 to the clock generator B 71,which correspondingly produces a 7.2 MHz clock signal that issynchronized with the periodic chrominance bursts in the video/datainput signal. This 7.2 MHz clock signal is utilized in producing clockpulse bursts, synchronized with the video/data input signal, forclocking the successive packets of digital audio data, included in theinput signal, into a memory M 77.

To produce the 7.2 MHz clock pulse bursts, for clocking the digitalaudio data into the memory B 77, the 7.2 MHz clock signal is coupledover line 81 from the clock generator B 71 to one input terminal of anAND gate 83. Simultaneously, the sequence controller B 69 produces thevertical blanking and horizontal blanking signals for coupling overlines 85 and 87, respectively, to two additional input terminals of theAND gate. The AND gate therefore produces a succession of clock pulsebursts, at a bit rate of 7.2 MHz, coinciding with the timing of the bitpackets of the time-compressed digital audio signal portion of thevideo/data input signal.

This clock pulse burst signal is coupled over line 89 from the AND gate83 to the clock in terminal of the memory B 77, to load into the memorythe successive bits of the normalized video/data input signal, which iscoupled over line 91 form the data normalizer 67 to the data inputterminal of the memory B. Similar to the memory A 31 of the recordformatting apparatus (FIG. 1), the memory B 77 of the playbackformatting apparatus (FIG. 2) can advantageously comprise about ten16K×1 dynamic RAM integrated circuits, connected in a conventionalmanner.

After the digital data from one entire frame of the video/data inputsignal, representative of about 13 seconds of the original analog audiosignal, has been clocked into the memory B 77 for storage, the sequencecontroller B 69 terminates the 7.2 MHz enable signal, to likewiseterminate the clock pulse burst signal coupled to the clock in terminalof the memory B. Thereafter, for the following frame of the video/datainput signal, i.e., while the video frame corresponding to the storeddigital audio data is present, the digital data being stored in thememory B is clocked out at a 12 kilobit per second rate and converted toits original analog format for playback simultaneous with a repeateddisplay of the video frame.

To accomplish this conversion, the sequence controller B 69 outputs a 12KHz enable signal for coupling over line 93 to the clock generator B 71,which, accordingly, outputs a 12 KHz clock signal for coupling over line95 to a clock out terminal of the memory B 77. As a result, a 12 kilobitper second intermediate digital data signal is output by the memory Band coupled over line 97 from the output terminal of the memory B to anadaptive delta modulator 99, for conversion back to its original analogformat. The demodulator, which is also clocked by the 12 KHz clocksignal, can be constructed in a manner set forth in the aforementionedarticle written by N. S. Jayant.

The analog audio output signal produced by the adaptive deltademodulator 99 is then coupled over line 101 to a suitable audio speaker(not shown) for playback while the player machine is playing back thecorresponding video frame for display on a video monitor (not shown),the prescribed number of times. Suitable stop-motion playback apparatusfor scanning a selected recording track, in a repeated fashion, andthereby playing back a video frame recorded on the track in astop-motion fashion, is disclosed in U.S. Pat. No. 4,332,022, issued May25, 1982, commonly assigned and filed in the name of Ludwig Ceshkovsky,et al and entitled "Tracking System and Method for Video Disc Player",and which is a division of application Ser. No. 890,670, entitled "VideoDisc Player", filed Mar. 27, 1978, now abandoned. In a conventionalmanner, the playback apparatus can be made, and responsive to thespecial flag code recorded in the vertical interval of the frame, toscan the track the prescribed number of times.

Referring to FIG. 4, there is shown a block diagram of a prior artvideodisc player system with which the present invention can be used.The player employs an optical system indicated at 202 and shown ingreater detail in FIG. 5.

Referring collectively to FIGS. 4 and 5, the optical system 202 includesa read laser 203 employed for generating a read beam 204 which is usedfor reading a frequency modulated encoded signal stored on a video disk11. The read beam 204 is polarized in a predetermined direction. Theread beam 204 is directed to the video disc 11 by the optical system202. An additional function of the optical system 202 is to focus thelight beam down to a spot at its point of impingement with the videodisc 11.

A portion of an information bearing surface of the video disc 11 isshown enlarged within a circle 208. A plurality of information tracks209 are formed on the video disc 11. Each track is formed withsuccessive light reflective regions 210 and light non-reflective regions211. The direction of reading is indicated by an arrow 212. The readbeam 204 has two degrees of movement, the first of which is in theradial direction as indicated by a double headed arrow 213, the secondof which is the tangential direction as indicated by a double headedarrow 214. The double heads of each of the arrows 213 and 214 indicatethat the read beam 204 can move in both directions in each degree ofmovement.

Referring to FIG. 5, the optical system comprises a lens 215 employedfor shaping the beam to fully fill an entrance aperture 216 of amicroscopic objective lens 217. The objective lens is employed forforming the spot 206 of light at its point of impingement with the videodisc 11.

After the beam 204 is properly formed by the lens 215, it passes througha diffraction grating 218 which splits the read beam into three separatebeams. Two of the beams (the outer two) are employed for developing aradial tracking error and the other is used for developing both a focuserror signal and the information signal. The output for the diffractiongrating 218 is applied to a beam splitting prism 220. The transmittedportion of the beam 204 is applied through a quarter wave plate 222which provides a ninety degree shift in polarization of the lightforming the beam 204. The read beam next impinges upon a fixed mirror224 which re-directs the read beam 204 to a first articulated mirror226. The function of the first articulated mirror 226 is to move thelight beam in a first degree of motion which is tangential to thesurface of the video disc 11 to correct for time base errors introducedinto the reading beam 204 because of eccentricities in the manufactureof the disc 11. The read beam 204 now impinges upon the entranceaperture 216, and is focused to a spot 206 upon the information bearingtrack 209 of the video disc 11 by the lens 217.

The first articulated mirror 226 directs the light beam to a secondarticulated mirror 228. The second articulated mirror 228 is employed asa tracking mirror. It is the function of the tracking mirror 228 torespond to tracking error signals so as to slightly change its physicalposition to direct the point of impingement 206 of the read beam 204 soas to radially track the information carrying indicia on the surface ofthe video disc 11.

In normal playing mode, the focused beam of light impinges uponsuccessively positioned light reflective regions 210 and lightnon-reflective regions 211 representing the frequency modulatedinformation. IN the preferred embodiment, the light non-reflectiveregions 211 are light scattering elements carried by the videodisc 11.The modulated light beam is a light equivalent of the electricalfrequency modulated signal containing all the recorded information. Thismodulated light beam is generated by the microscopic objective lens 217by gathering, or not, reflected light from the reflective region 210 andlight non-reflective regions 211 on the video disc 11. The reflectedportion of the read beam is indicated at 204'. The reflected read beam204' retraces the same path previously explained by impinging insequence upon the second articulated mirror 228, the first articulatedmirror 226, and the fixed mirror 224. The reflected read beam 204' nextpasses through the quarterwave plate 222.

The quarterwave plate 222 provides an additional ninety degreepolarization shift resulting in a total of one hundred eighty degrees inshift of polarization to the reflected read beam 204'. The reflectedread beam 204' now impinges upon the beam splitting prism 220, whichprism diverts the reflected read beam 204' to impinge upon a signalrecovery subsystem indicated generally at 230.

Referring to FIG. 4, the normal operating mode of the signal recoverysybsystem 230 is to provide a plurality of informational signals to theremaining portion of the player. These informational signals fallgenerally into two types, one being an information signal itself whichrepresents the stored information. A second type of signal is a controlsignal derived from the informational signals for controlling variousportions of the player. The informational signal is a frequencymodulated signal representing the information stored on the video disc22. The informational signal is applied to an FM processing subsystemindicated at 232 over a line 234. A control signal generated by thesignal recovery subsystem 230 is a differential tracking error signalapplied to a tracking servo subsystem 240 over a line 242. Thedifferential tracking error signal from the signal recovery subsystem230 is also applied to a stop motion subsystem indicated at 244 over theline 242 and a second line 246.

Upon receipt of the START pulse generated in a function generator 247,the first function of the video disc player is to activate the laser203, activate a spindle motor 248, causing an integrally attachedspindle 249 and its video disc member 11 mounted thereon to beginspinning.

The frequency modulated signal read from the disc needs additionalprocessing to achieve optimum fidelity during the display in thetelevision receiver 296. In review of the stop motion mode of operation,the following combinations occur in the preferred embodiment. In a firstembodiment, the differential tracking error signal is removed from thetracking mirror 228 and a stop motion pulse is substituted therefor tocause the radial tracking mirror 228 to jump one track from that trackbeing played. The differential tracking error is reaapplied into thetracking servo subsystem 240 and cooperates with the stop motion pulse206 applied to the radial tracking mirror 228 to reacquire radialtracking. The differential tracking error can be reentered into thetracking servo system for optimum results.

The sequence controller B 69 of the playback formatting apparatusfurther operates to produce a squelch signal for output on line 103whenever an analog audio signal is not being output by the apparatus.This squelch signal can be utilized to insure that the audio signal iscoupled to the speaker only when it is being output by the deltademodulator 99.

In an alternative embodiment of the present invention (not shown in thedrawings), the time-compressing audio signal recorded on the disc is inan analog format. The signal is formatted by initially periodicallysampling the original analog audio signal and storing the successivesamples in an analog memory device, such as a charge coupled device(CCD). The successive samples are then extracted from the memory deviceat a relatively high rate and interleaved with conventional videosynchronization signals, to produce the time-compressed audio signal.

From the foregoing description, it should be apparent that the presentinvention provides a record disc, along with record formatting apparatusfor producing a special composite audio and video signal for recordingon the disc, and playback formatting apparatus for separating the audioinformation from the signal recovered from the disc and for re-creatingthe original analog audio signal, wherein the record disc can be playedback in a stop-motion fashion, with accompanying audio, while utilizinga minimum number of recording tracks on the disc. Each segment of theanalog audio signal is converted to a digital format and compressed intime, for recording on a single track on the disc, while thecorresponding video frame is recorded on an adjacent track.

Although the invention has been described in detail with reference toits presently preferred embodiment, it will be understood by one ofordinary skill in the art that various modifications can be made,without departing from the spirit and scope of the invention.Accordingly, it is not intended that the invention be limited, except asby the appended claims.

I claim:
 1. A record disc for storing a composite signal that includessegments of video information and corresponding segments of audioinformation related to the video information, comprising:a plurality ofcircular video information-containing tracks having a video informationsegment stored therein in real-time, each said video information segmentcontaining a single video frame in conventional video format including aconventional type of video synchronizing signal; and a plurality ofcircular audio information-containing tracks, each said audioinformation-containing track corresponding with one of said videoinformation containing tracks and having at least a portion of an audioinformation segment which has a prescribed real-time length related tosaid single video frame in said corresponding video informationcontaining track, said audio information segment stored therein intime-compressed digital data format, each of said audio informationsegments including packets of digital data interleaved with saidconventional type of video synchronizing signals, adjacent ones of saidaudio information packets on said disc representing a continuous portionof the stored audio information segment; and wherein each pair of audioinformation-containing track and corresponding videoinformation-containing track includes a coded signal, included in saidconventional video synchronizing signals in one of said audioinformation-containing tracks or said video information-containingtracks, which is indicative of an equivalent real-time length of therespective time-compressed audio information segment, to indicate howlong said video signal should be displayed.
 2. A disc as in claim 1,wherein said circular tracks are concentric tracks.